Benjamin j



UNITED STATES PATENT OFFICE.

BENJAMIN J. MILLER, OF NEW YORIQN. Y.

MODE OF FORMING A SPIRAL FLUE FOR STEAM-BOILERS.

Specification forming part of Letters Patent No. 675, dated April 5, 1838.

.To all whom it may concern:

Be it known that I, BENJAMIN J. MILLER,

of the city and State 0f New York, have invented a new and useful Improvement in Fines for Steannoilers; and I do hereby declare that the following is an exact and full description.

The nature of my improvement consists in the application to ordinary low-pressure boilers lues of a spiral form, as hereinafter described, for the purpose of obtaining more compactnes and strength than in the common ,method concentric. A spiral-slot or opening c, corresponding in each, extends from one end of the iiue to the other, and the slot or opening thus made is preserved and the flue made com plete by closing or joining the corresponding spiral edges ot' both cylinders, so that water may `flow from the inside of the inner cylinder to the outside of the outer one, and the iiame or heated air pass through the inclosed channel between the outside surface of the inner cylinder and the inside surface of the outer one until it reaches the chimney Yol. I make use of brace or socket bolts to give stability to such parts of the iue as may from its size or circumstances require support or strength.

Vhat I claim as my invention, and desire to secure by Letters Patent, is

The construction and application of one or more spiral fiues to steam-boilers, as above substantially described.

BENJAMIN J. MILLER. Titnessesz WM. A. GUMMINes, FRANKLIN W. STILLMAN. 

